.\" Written Sat Mar  8 10:35:08 MEZ 1997 by
.\" J. "MUFTI" Scheurich (mufti@csv.ica.uni-stuttgart.de)
.\"
.\" %%%LICENSE_START(GPL_NOVERSION_ONELINE)
.\" This page is licensed under the GNU General Public License
.\" %%%LICENSE_END
.\"
.TH __SETFPUCW 3 2021-03-22 "Linux" "Linux Programmer's Manual"
.SH NAME
__setfpucw \- set FPU control word on i386 architecture (obsolete)
.SH SYNOPSIS
.nf
.B #include <i386/fpu_control.h>
.PP
.BI "void __setfpucw(unsigned short " control_word );
.fi
.SH DESCRIPTION
.BR __setfpucw ()
transfers
.I control_word
to the registers of the FPU (floating-point unit) on the i386 architecture.
This was used to control floating-point precision,
rounding and floating-point exceptions.
.SH CONFORMING TO
This function was a nonstandard GNU extension.
.SH NOTES
As of glibc 2.1 this function does not exist anymore.
There are new functions from C99, with prototypes in
.IR <fenv.h> ,
to control FPU rounding modes, like
.BR fegetround (3),
.BR fesetround (3),
and the floating-point environment, like
.BR fegetenv (3),
.BR feholdexcept (3),
.BR fesetenv (3),
.BR feupdateenv (3),
and FPU exception handling, like
.BR feclearexcept (3),
.BR fegetexceptflag (3),
.BR feraiseexcept (3),
.BR fesetexceptflag (3),
and
.BR fetestexcept (3).
.PP
If direct access to the FPU control word is still needed, the
.B _FPU_GETCW
and
.B _FPU_SETCW
macros from
.I <fpu_control.h>
can be used.
.SH EXAMPLES
.B __setfpucw(0x1372)
.PP
Set FPU control word on the i386 architecture to
     \- extended precision
     \- rounding to nearest
     \- exceptions on overflow, zero divide and NaN
.SH SEE ALSO
.BR feclearexcept (3)
.PP
.I <fpu_control.h>
.SH COLOPHON
This page is part of release 5.13 of the Linux
.I man-pages
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
\%https://www.kernel.org/doc/man\-pages/.
